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Shalnov [3]
2 years ago
9

The teacher tells your group to make a stock solution of sodium chloride, and then diluting it to

Chemistry
1 answer:
sergejj [24]2 years ago
3 0

The idea here is that you need to figure out how many moles of magnesium chloride,

MgCl

2

, you need to have in the target solution, then use this value to determine what volume of the stock solution would contain this many moles.

As you know, molarity is defined as the number of moles of solute, which in your case is magnesium chloride, divided by liters of solution.

c

=

n

V

So, how many moles of magnesium chloride must be present in the target solution?

c

=

n

V

⇒

n

=

c

⋅

V

n

=

0.158 M

⋅

250.0

⋅

10

−

3

L

=

0.0395 moles MgCl

2

Now determine what volume of the target solution would contain this many moles of magnesium chloride

c

=

n

V

⇒

V

=

n

c

V

=

0.0395

moles

3.15

moles

L

=

0.01254 L

Rounded to three sig figs and expressed in mililiters, the volume will be

V

=

12.5 mL

So, to prepare your target solution, use a

12.5-mL

sample of the stock solution and add enough water to make the volume of the total solution equal to

250.0 mL

.

This is equivalent to diluting the

12.5-mL

sample of the stock solution by a dilution factor of

20

.

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qaws [65]

Answer:

Increasing atomic number - True

Explanation:

The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing atomic number instead of atomic mass.

The Atomic number is the number of protons in an atom, and this number is unique for each element. For example, Hydrogen has an atomic number of 1, Calcium has an atomic number of 20.

In the modern periodic table the elements are further arranged into:

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3 years ago
What is the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen
natta225 [31]
Carbon(C):
number of moles= mass/molar mass(Mr)
=65.5/12
=5.5 moles

Hydrogen(H):
number of moles=mass/molar mass (Mr)
=5.5/1
=5.5 moles

Oxygen (O):
number of moles = mass/molar mass (Mr)
=29.0/16
=1.8 moles

EF= lowest number of moles over each of the elements

So,
C= 5.5/1.8 = 3
H= 5.5/1.8 = 3
O= 1.8/1.8 = 1

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romanna [79]

Answer:

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Explanation:

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Tems11 [23]

Answer:

The answer is D. gamma rays

Explanation:

A radioactive atom can have three different types of emission:

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Beta particles (β) = they have 5x10^{-4} amu and they have an intermediate penetrating power

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